下面的代码示例显示从文本文件读取文本的简单方法。
[Visual Basic]
Imports System
Imports System.IO
Class Test
Public Shared Sub Main()
Try
' Create an instance of StreamReader to read from a file.
Dim sr As StreamReader = New StreamReader("TestFile.txt")
Dim line As String
' Read and display the lines from the file until the end
' of the file is reached.
Do
line = sr.ReadLine()
Console.WriteLine(Line)
Loop Until line Is Nothing
sr.Close()
Catch E As Exception
' Let the user know what went wrong.
Console.WriteLine("The file could not be read:")
Console.WriteLine(E.Message)
End Try
End Sub
End Class
[C#]
using System;
using System.IO;
class Test
{
public static void Main()
{
try
{
// Create an instance of StreamReader to read from a file.
// The using statement also closes the StreamReader.
using (StreamReader sr = new StreamReader("TestFile.txt"))
{
String line;
// Read and display lines from the file until the end of
// the file is reached.
while ((line = sr.ReadLine()) != null)
{
Console.WriteLine(line);
}
}
}
catch (Exception e)
{
// Let the user know what went wrong.
Console.WriteLine("The file could not be read:");
Console.WriteLine(e.Message);
}
}
}
下面的代码示例读取整个文件，并在检测到文件尾时发出通知。
[Visual Basic]
Option Explicit On
Option Strict On
Imports System
Imports System.IO
Public Class TextFromFile
Private Const FILE_NAME As String = "MyFile.txt"
Public Shared Sub Main()
If Not File.Exists(FILE_NAME) Then
Console.WriteLine("{0} does not exist.", FILE_NAME)
Return
End If
Dim sr As StreamReader = File.OpenText(FILE_NAME)
Dim input As String
input = sr.ReadLine()
While Not input Is Nothing
Console.WriteLine(input)
input = sr.ReadLine()
End While
Console.WriteLine("The end of the stream has been reached.")
sr.Close()
End Sub
End Class
[C#]
using System;
using System.IO;
public class TextFromFile
{
private const string FILE_NAME = "MyFile.txt";
public static void Main(String[] args)
{
if (!File.Exists(FILE_NAME))
{
Console.WriteLine("{0} does not exist.", FILE_NAME);
return;
}
StreamReader sr = File.OpenText(FILE_NAME);
String input;
while ((input=sr.ReadLine())!=null)
{
Console.WriteLine(input);
}
Console.WriteLine ("The end of the stream has been reached.");
sr.Close();
}
}
此代码通过调用 File.OpenText 创建一个指向 MyFile.txt 的 StreamReader。StreamReader.ReadLine 将每一行都返回为一个字符串。当没有要读取的字符时，一条消息显示该情况，然后流关闭。